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Sunday, 11 May 2014

Fiat lux, deux

Some research with super-bright LEDs.

I connected up the 3w red led with a voltage reducer and an ammeter that doesn't care about voltage. And, because I thought it might get hot, I dug out a heat sink from an ancient 700 mhz Duron cpu (now you see why I'm reluctant to throw things away), and stuck the led to that. Then I put 700 ma through it, by turning up the wick on the voltage reducer until at about three volts, I had 700 ma (that's what the specs say it's rated to). It was, of course, too bright to look at, and when I put the infra-red temperature sensor on it, it wasn't getting hot (or if it was, the heat sink was doing its job). So that project's looking good.

Then I tried the 10w white led. Again, I mounted it on the heat sink. Last time I tried this led, it got too hot to touch; this time, mounted on the heat sink, it didn't. Not only was it too bright to look at, I still have spots in my eyes several minutes later!

So these are going to mke great car-repelling bike lights. I've also ordered a strip of red leds; I plan to use that to decorate the back of the bike, so that it looks like a mobile Christmas tree.

I have a couple of different flashers on order, so I'll be experimenting with those when they arrive. And I have to think about a mounting and housing for the bright leds. Maybe a torch that's stopped working?

This afternoon, we're going to an engagement party; wife's brother's wife's brother's daughter. And next week is The Wedding. I've been polishing my Father-of-the-Bride speech.

Tomorrow, I have a parcel to pick up from the post office in Amersham; something from China, I think, but I can't guess what. And I need to go to Chesham to pick up my eye drops and my regular Warfarin-and-Statin prescription, so I'll go on the Forza bike. It'll take longer and be more effort than taking the car, but it's good exercise and parking is easy.